This invention relates to building walls and, in particular, to insulated walls having outer layers of poured concrete and an inner layer of rigid insulation therebetween. It is well known in the industry to utilize a pair of opposed parallel outer layers of concrete with an inner layer of cellular insulation, provided for the purpose of improving the insulating efficiency of the poured wall. U.S. Pat. Nos. 2,653,469 and 4,329,821 disclose such walls. A long sought after, but heretofore unfulfilled, objective in the manufacture of such insulated concrete walls is the ability to pour the concrete into the forms with a single concrete pouring step. U.S. Pat. No. 4,329,821 sets out one attempt to achieve a single stage pour. A spaced series of pins or tie rods extend through the insulating layer and are of sufficient length to barely touch the opposed forms. Each pin or tie rod includes a pair of washers which are positioned directly adjacent the outer surface of the insulation wall to prevent shifting of the pin during concrete pouring. The success of this method is dependent upon the uniformity of the concrete pouring step on each side of the insulation and on the inherent strength of the insulation panel. This method provides inconsistent support using a single stage pour, due to the localized support provided by the spaced apart tie rods or pins. When the concrete accumulates more quickly on one side of the insulation, the insulation board has a tendency to shift despite the presence of those pins. The placement of the individual pins and washers at a multiplicity of locations on the insulation board is labor intensive. Further, the system disclosed in U.S. Pat. No. 4,329,821 is not useful for walls having angles and corners, since the pins must have abutting forms on both sides for transverse placement. It also does not provide a reinforced wall structure, particularly when non-metallic pins or tie rods are utilized.
It is an object of the present invention to provide an efficient method of securely positioning insulation panels between the concrete forms. It is a further object of the invention to provide a reinforced, insulated wall structure using a single step concrete pouring method. Yet another object is to provide a composite, insulated, concrete wall in which the layers are bonded together by transverse reinforcing members to provide a monolithic wall structure upon completion.